IMPELLER
The impeller (Fig. 225) is an integral part of the
converter housing. The impeller consists of curved
blades placed radially along the inside of the housing
on the transmission side of the converter. As the con-
verter housing is rotated by the engine, so is the
impeller, because they are one and the same and are
the driving members of the system.
TURBINE
The turbine (Fig. 226) is the output, or driven,
member of the converter. The turbine is mounted
within the housing opposite the impeller, but is not
attached to the housing. The input shaft is inserted
through the center of the impeller and splined into
the turbine. The design of the turbine is similar to
the impeller, except the blades of the turbine are
curved in the opposite direction.
STATOR
The stator assembly (Fig. 227) is mounted on a sta-
tionary shaft which is an integral part of the oil
pump. The stator is located between the impeller and
turbine within the torque converter case (Fig. 228).
The stator contains a freewheeling clutch, which
allows the stator to rotate only in a clockwise direc-
tion. When the stator is locked against the freewheel-
ing clutch, the torque multiplication feature of the
torque converter is operational.Fig. 223 Transmission Temperature Sensor
Specifications
Fig. 224 Torque Converter
1 - TURBINE
2 - IMPELLER
3-STATOR
4 - INPUT SHAFT
5 - STATOR SHAFT
21 - 142 AUTOMATIC TRANSMISSION - NAG1VA
TORQUE CONVERTER (Continued)
STATOR
Torque multiplication is achieved by locking the
stator's over-running clutch to its shaft (Fig. 230).
Under stall conditions (the turbine is stationary), the
oil leaving the turbine blades strikes the face of the
stator blades and tries to rotate them in a counter-
clockwise direction. When this happens the over-run-
ning clutch of the stator locks and holds the stator
from rotating. With the stator locked, the oil strikes
the stator blades and is redirected into a ªhelpingº
direction before it enters the impeller. This circula-
tion of oil from impeller to turbine, turbine to stator,
and stator to impeller, can produce a maximum
torque multiplication of about 2.0:1. As the turbine
begins to match the speed of the impeller, the fluid
that was hitting the stator in such as way as to
cause it to lock-up is no longer doing so. In this con-
dition of operation, the stator begins to free wheel
and the converter acts as a fluid coupling.
Fig. 228 Stator Location
1-STATOR
2 - IMPELLER
3 - FLUID FLOW
4 - TURBINEFig. 229 Torque Converter Lock-up Clutch
1 - TURBINE
2 - IMPELLER
3-STATOR
4 - INPUT SHAFT
5 - STATOR SHAFT
6 - PISTON
7 - COVER SHELL
8 - INTERNALLY TOOTHED DISC CARRIER
9 - CLUTCH PLATE SET
10 - EXTERNALLY TOOTHED DISC CARRIER
Fig. 230 Stator Operation
1 - DIRECTION STATOR WILL FREE WHEEL DUE TO OIL
PUSHING ON BACKSIDE OF VANES
2 - FRONT OF ENGINE
3 - INCREASED ANGLE AS OIL STRIKES VANES
4 - DIRECTION STATOR IS LOCKED UP DUE TO OIL PUSHING
AGAINST STATOR VANES
VAAUTOMATIC TRANSMISSION - NAG1 21 - 145
TORQUE CONVERTER (Continued)
TORQUE CONVERTER CLUTCH (TCC)
In a standard torque converter, the impeller and
turbine are rotating at about the same speed and the
stator is freewheeling, providing no torque multipli-
cation. By applying the turbine's piston and friction
material (Fig. 231) to the front cover, a total con-
verter engagement can be obtained. The result of this
engagement is a direct 1:1 mechanical link between
the engine and the transmission.
The clutch can be engaged in second, third, fourth,
and fifth gear ranges.
The TCM controls the torque converter by way of
internal logic software. The programming of the soft-
ware provides the TCM with control over the torque
converter solenoid. There are four output logic states
that can be applied as follows:
²No EMCC
²Partial EMCC
²Full EMCC
²Gradual-to-no EMCCNO EMCC
Under No EMCC conditions, the TCC Solenoid is
OFF. There are several conditions that can result in
NO EMCC operations. No EMCC can be initiated
due to a fault in the transmission or because the
TCM does not see the need for EMCC under current
driving conditions.
PARTIAL EMCC
Partial EMCC operation modulates the TCC Sole-
noid (duty cycle) to obtain partial torque converter
clutch application. Partial EMCC operation is main-
tained until Full EMCC is called for and actuated.
During Partial EMCC some slip does occur. Partial
EMCC will usually occur at low speeds, low load and
light throttle situations.
FULL EMCC
During Full EMCC operation, the TCM increases
the TCC Solenoid duty cycle to full ON after Partial
EMCC control brings the engine speed within the
desired slip range of transmission input speed rela-
tive to engine rpm.
GRADUAL-TO-NO EMCC
This operation is to soften the change from Full or
Partial EMCC to No EMCC. This is done at mid-
throttle by decreasing the TCC Solenoid duty cycle.
REMOVAL
(1) Remove transmission and torque converter
from vehicle.
(2) Place a suitable drain pan under the converter
housing end of the transmission.
CAUTION: Verify that transmission is secure on the
lifting device or work surface, the center of gravity
of the transmission will shift when the torque con-
verter is removed creating an unstable condition.
The torque converter is a heavy unit. Use caution
when separating the torque converter from the
transmission.
(3) Pull the torque converter forward until the cen-
ter hub clears the oil pump seal.
(4) Separate the torque converter from the trans-
mission.
INSTALLATION
Check converter hub and drive flats for sharp
edges, burrs, scratches, or nicks. Polish the hub and
flats with 320/400 grit paper or crocus cloth if neces-
sary. The hub must be smooth to avoid damaging the
pump seal at installation.
(1) Lubricate oil pump seal lip with transmission
fluid.
Fig. 231 Torque Converter Lock-up Clutch
1 - TURBINE
2 - IMPELLER
3-STATOR
4 - INPUT SHAFT
5 - STATOR SHAFT
6 - PISTON
7 - COVER SHELL
8 - INTERNALLY TOOTHED DISC CARRIER
9 - CLUTCH PLATE SET
10 - EXTERNALLY TOOTHED DISC CARRIER
21 - 146 AUTOMATIC TRANSMISSION - NAG1VA
TORQUE CONVERTER (Continued)
TIRES/WHEELS
TABLE OF CONTENTS
page page
TIRES/WHEELS
DIAGNOSIS AND TESTING - TIRE AND
WHEEL RUNOUT......................1
STANDARD PROCEDURE
STANDARD PROCEDURE - MATCH
MOUNTING...........................2
STANDARD PROCEDURE - TIRE AND
WHEEL BALANCE......................3
STANDARD PROCEDURE - TIRE ROTATION . 5
SPECIFICATIONS
TORQUE CHART......................5
TIRES
DESCRIPTION
DESCRIPTION - TIRES..................6
DESCRIPTION - RADIAL ± PLY TIRES......6
DESCRIPTION - TIRE PRESSURE FOR
HIGH SPEEDS.........................6
DESCRIPTION - REPLACEMENT TIRES.....7
DESCRIPTION - TIRE INFLATION
PRESSURES..........................7
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - PRESSURE
GAUGES.............................8
DIAGNOSIS AND TESTING - TIRE NOISE
OR VIBRATION........................8
DIAGNOSIS AND TESTING - TREAD WEAR
INDICATORS..........................8DIAGNOSIS AND TESTING - TIRE WEAR
PATTERNS...........................8
DIAGNOSIS AND TESTING - TIRE/VEHICLE
LEAD................................8
STANDARD PROCEDURE - REPAIRING
LEAKS..............................10
CLEANING............................10
SPECIFICATIONS
TIRES..............................10
SPARE TIRE CARRIER
REMOVAL.............................10
INSTALLATION.........................10
WHEELS
DESCRIPTION.........................11
OPERATION...........................11
DIAGNOSIS AND TESTING
WHEEL INSPECTION..................11
STANDARD PROCEDURE
STANDARD PROCEDURE - WHEEL
REPLACEMENT.......................11
STANDARD PROCEDURE - DUAL REAR
WHEEL INSTALLATION.................12
REMOVAL.............................13
INSTALLATION.........................13
TIRES/WHEELS
DIAGNOSIS AND TESTING - TIRE AND WHEEL
RUNOUT
Radial runout is the difference between the high
and low points on the tire or wheel (Fig. 1).
Lateral runout is thewobbleof the tire or wheel.
Radial runout of more than 1.5 mm (.060 inch)
measured at the center line of the tread may cause
the vehicle to shake.
Lateral runout of more than 2.0 mm (.080 inch)
measured near the shoulder of the tire may cause the
vehicle to shake.
Sometimes radial runout can be reduced. Relocate
the wheel and tire assembly on the mounting studs
(See Method 1). If this does not reduce runout to an
acceptable level, the tire can be rotated on the wheel.
(See Method 2).
Fig. 1 Checking Tire/Wheel/Hub Runout
1 - RADIAL RUNOUT
2 - LATERAL RUNOUT
VATIRES/WHEELS 22 - 1
METHOD 1 (RELOCATE WHEEL ON HUB)
(1) Drive vehicle a short distance to eliminate tire
flat spotting from a parked position.
(2) Check wheel bearings and adjust if adjustable
or replace if necessary.
(3) Check the wheel mounting surface.
(4) Relocate wheel on the mounting, two studs
over from the original position.
(5) Tighten wheel nuts until all are properly
torqued, to eliminate brake distortion.
(6) Check radial runout. If still excessive, mark
tire sidewall, wheel, and stud at point of maximum
runout and proceed to Method 2.
METHOD 2 (RELOCATE TIRE ON WHEEL)
NOTE: Rotating the tire on wheel is particularly
effective when there is runout in both tire and
wheel.
(1) Remove tire from wheel and mount wheel on
service dynamic balance machine.
(2) Check wheel radial runout (Fig. 2) and lateral
runout (Fig. 3).
²STEEL WHEELS: Radial runout 0.031 in., Lat-
eral runout 0.031 in. (maximum)
²ALUMINUM WHEELS: Radial runout 0.020 in.,
Lateral runout 0.025 in. (maximum)
(3) If point of greatest wheel lateral runout is near
original chalk mark, remount tire 180 degrees.
Recheck runout, Refer to match mounting procedure.
STANDARD PROCEDURE
STANDARD PROCEDURE - MATCH MOUNTING
Wheels and tires are match mounted at the factory.
This means that the high spot of the tire is matched
to the low spot on the wheel rim. Each are marked
with a bright colored temporary label on the out-
board surface for alignment. The wheel is also
marked permanently on the inside of the rim in the
tire well. This permanent mark may be a paint dot
or line, a permanent label or a stamped impression
such as an X. An optional location mark is a small
spherical indentation on the vertical face of the out-
board flange on some non styled base steel wheels.
The tire must be removed to locate the permanent
mark on the inside of the wheel.
Before dismounting a tire from its wheel, a refer-
ence mark should be placed on the tire at the valve
stem location. This reference will ensure that it is
remounted in the original position on the wheel.
(1) Remove the tire and wheel assembly from the
vehicle and mount on a service dynamic balance
machine.
(2) Measure the total runout on the center of the
tire tread rib with a dial indicator. Record the indi-
cator reading. Mark the tire to indicate the high spot.
Place a mark on the tire at the valve stem location
(Fig. 4).
(3) Break down the tire and remount it 180
degrees on the rim (Fig. 5).
(4) Measure the total indicator runout again. Mark
the tire to indicate the high spot.
Fig. 2 Radial Runout
1 - MOUNTING CONE
2 - SPINDLE SHAFT
3 - WING NUT
4 - PLASTIC CUP
5 - DIAL INDICATOR
6 - WHEEL
7 - DIAL INDICATOR
Fig. 3 Lateral Runout
1 - MOUNTING CONE
2 - SPINDLE SHAFT
3 - WING NUT
4 - PLASTIC CUP
5 - DIAL INDICATOR
6 - WHEEL
7 - DIAL INDICATOR
22 - 2 TIRES/WHEELSVA
TIRES/WHEELS (Continued)
(5) If runout is still excessive, the following proce-
dures must be done.
²If the high spot is within 101.6 mm (4.0 in.) of
the first spot and is still excessive, replace the tire.
²If the high spot is within 101.6 mm (4.0 in.) of
the first spot on the wheel, the wheel may be out of
specifications. Refer to Wheel and Tire Runout.
²If the high spot is NOT within 101.6 mm (4.0
in.) of either high spot, draw an arrow on the tread
from second high spot to first. Break down the tire
and remount it 90 degrees on rim in that direction
(Fig. 6). This procedure will normally reduce the
runout to an acceptable amount, if not replace the
rim.
STANDARD PROCEDURE - TIRE AND WHEEL
BALANCE
It is recommended that a two plane service
dynamic balancer be used when a tire and wheel
assembly require balancing. Refer to balancer opera-
tion instructions for proper cone mounting proce-
dures. Typically use front cone mounting method for
steel wheels. For aluminum wheel use back cone
mounting method without cone spring.
NOTE: Static should be used only when a two plane
balancer is not available.
Fig. 4 First Measurement On Tire
1 - REFERENCE MARK
2 - 1ST MEASUREMENT HIGH SPOT MARK TIRE AND RIM
3 - WHEEL
4 - VALVE STEM
Fig. 5 Remount Tire 180 Degrees
1 - VALVE STEM
2 - REFERENCE MARK
Fig. 6 Remount Tire 90 Degrees In Direction of
Arrow
1 - 2ND HIGH SPOT ON TIRE
2 - 1ST HIGH SPOT ON TIRE
VATIRES/WHEELS 22 - 3
TIRES/WHEELS (Continued)
NOTE: Cast aluminum and forged aluminum wheels
require coated balance weights and special align-
ment equipment.
Wheel balancing can be accomplished with either
on or off vehicle equipment. When using on-vehicle
balancing equipment, remove the opposite wheel/tire.
Off-vehicle balancing is recommended.
For static balancing, find the location of the heavy
spot causing the imbalance. Counter balance wheeldirectly opposite the heavy spot. Determine weight
required to counter balance the area of imbalance.
Place half of this weight on theinnerrim flange and
the other half on theouterrim flange (Fig. 7).
For dynamic balancing, the balancing equipment is
designed to locate the amount of weight to be applied
to both the inner and outer rim flange (Fig. 8).
Fig. 7 Static Unbalance & Balance
1 - HEAVY SPOT
2 - CENTER LINE OF SPINDLE
3 - ADD BALANCE WEIGHTS HERE4 - CORRECTIVE WEIGHT LOCATION
5 - TIRE OR WHEEL TRAMP, OR WHEEL HOP
Fig. 8 Dynamic Unbalance & Balance
1 - CENTER LINE OF SPINDLE
2 - ADD BALANCE WEIGHTS HERE3 - CORRECTIVE WEIGHT LOCATION
4 - HEAVY SPOT WHEEL SHIMMY AND VIBRATION
22 - 4 TIRES/WHEELSVA
TIRES/WHEELS (Continued)
STANDARD PROCEDURE - TIRE ROTATION
Tires on the front and rear axles operate at differ-
ent loads and perform different steering, driving, and
braking functions. For these reasons, the tires wear
at unequal rates. They may also develop irregular
wear patterns. These effects can be reduced by rotat-
ing the tires according to the maintenance schedule
in the Owners Manual. This will improve tread life,
traction and maintain a smooth quiet ride.
The recommended method of tire rotation is (Fig.
9) & (Fig. 10). Other methods can be used, but may
not provide the same tire longevity benefits.CAUTION: 3500 Dual rear tires have a new tire rota-
tion pattern. This is to accommodate the asymmet-
rical design of the ON/OFF road tires and the use of
the outlined white letter (OWL) tires. When replac-
ing a flat, the spare tire may have to be remounted
on the rim or installed at a different location to
maintain the correct placement of the asymmetrical
design or the (OWL).
SPECIFICATIONS
TORQUE CHART
TORQUE SPECIFICATIONS
DESCRIPTION N´m Ft. Lbs. In. Lbs.
Models
690.6,901,902,903,904,905, WD2YD441,YD541190 +10 140 +10 ±
Models
WD5.WD141,WD241,WD341,WD2.YD141,YD241,YD341240 +10 177 +10 ±
Fig. 9 TIRE ROTATION PATTERN - SINGLE REAR
WHEEL (SRW)
Fig. 10 TIRE ROTATION PATTERN - DUAL REAR
WHEELS (DRW)
VATIRES/WHEELS 22 - 5
TIRES/WHEELS (Continued)